Expert: Roger Zona - 6/22/2009

Question
QUESTION: Hi, I recently had my driveway removed and repaved with a new asphalt one, but I get temporary puddles that form when it rains.  These puddles (somewhat significant in size, I think) do not last very long -- they typically go away after a couple of hours once the rain stops, but I am concerned that there should not be standing water on a new driveway at all.  The contractor is telling me this is not a problem as long as there isn't standing water after 24 hours of a rainfall.  Is what he says true?  Keep in mind that this is a flat driveway and not the typical upward sloping one, so it was difficult to get a good slope, according to the contractor.  Thank you in advance for your help.

ANSWER: Dear Kamaljeet,

I don't agree with your contractor.  There should not be any "ponding" or "puddling" if installed correctly.  

Asphalt will compact continually.  For example, every time you drive onto the driveway, the asphalt compacts a fraction.  

When laying asphalt, the material placed is approx. 2" thick to compact to a 1" layer.  That's why the contractor uses a heavy duty roller-compactor and makes several passes.

If the rain water in the ponding areas goes away without evaporating, it's a good chance the water is being absorbed into the asphalt and eventually into the ground beneath.  The driveway should crown in the center and drain to either side, or crown on one edge and drain to the other edge.  Also, the drive should drain away from the garage doors.

Check the depth of your asphalt in several location.  a small plug that can be patched will tell you the actual dimension of material.  Does your contract specify a thickness?  - then the depth should not be any less.  If it is more, then perhaps it was not compacted enough.

I agree, it's tough getting a level and true asphalt surface but if it needs more asphalt, that's the contractors responsibility.

I hope this has been helpful.

Roger

---------- FOLLOW-UP ----------

QUESTION: Hi Roger,

Thank you for your response and information.  I am not sure if the rain water is evaporating or possibly being absorbed into the asphalt, but your comment brings up a point:  I need to measure how deep these puddles are.  I would imagine if they are 1/4" or less deep, then the water is most likely evaporating -- would you agree?  I kept an eye on the puddles over this past weekend when we had a few hours' worth of rain.  The puddles were completely gone within two hours of when the rain stopped.  

I will look into your suggestion of the asphalt depth.  Two questions, though:  if the asphalt is continually compacting, then won't the driveway eventually become uneven since I would imagine the compacting mostly takes place where the tires of the vehicles make contact with the driveway as I'm pulling my cars into and out of my garages?  Also, does it compact more just in four spots when I park a car on the driveway?  Thank you again.\

Kamaljeet

Answer
Dear Kamaljeet,

I live in Florida where the sun evaporates rain water quickly - but not in two hours.  The water is going somewhere else - either being absorbed into the asphalt or in fissures or cracks in the asphalt.  

As for the compaction - when asphalt is properly and thoroughly compacted, any additional compaction is very limited.  Yes, a car's weight will cause additional compaction but very gradually over a long period of time.  Here in Florida most of our streets, parking lots and even the turnpike are constructed of asphalt.  The constant traffic will cause additional compaction.  Yes, the weight of your car is distributed to the four tires and that's where the concentration of weight will cause the asphalt to compact if it is not properly compacted when installed.  

Good luck.

Roger